1. Field of the Invention
This invention relates to an illumination device used in performing flash photography or the like.
2. Description of the Related Art
In the conventional illumination devices of the above-stated kind arranged, for example, as disclosed in Japanese Laid-Open Patent Application No. SHO 57-150826, etc., a light emitting part of an electronic flash device is arranged to be fixedly held in position away from the optical axis of the photo-taking optical axis of a camera when the electronic flash device is being used and to be bent forward into a shape of being integral with the camera body when the electronic flash device is not being used. Another illumination device, disclosed in Japanese Laid-Open Patent Application No. SHO 59-165037, is arranged to converge a light flux emitted from a flash lamp into a strip-like shape through a light converging part and to obtain a desired distribution of luminous intensity through optical fibers disposed in the light converging part by bundling the optical fibers in a suitable manner.
The former arrangement cited above, however, has presented the following shortcomings. Since a flash lamp, a reflecting shade, etc., which constitute the swingable light emitting part of the electronic flash device are disposed at the fore end of a swingable part, the size of the light emitting part would be increased. Further, since the electronic flash device necessitates connection of electric parts for flashing, a sufficient reliability of the electronic flash device must be ensured against an electric shock, a repeating load on electric connection parts, etc. Therefore, the arrangement of the electronic flash device inevitably becomes complex and expensive.
The latter arrangement cited above, on the other hand, has presented the following shortcomings. In this arrangement, the optical fibers are bendably disposed in the light converging part, and the distribution of luminous intensity is controlled by the manner in which the optical fibers are bundled. However, since the optical fibers cannot be laid down and arranged without any gap, it is inevitable to have some loss of light quantity. Besides, the optical fibers are very expensive. In addition to these shortcomings, it is impossible to control the distribution of luminous intensity within the optical fibers (or a light transmitting part).